Analysis design and investigation of corrugated parallel plate waveguides

Traditional full-wave analyses of glide-symmetric double-corrugated parallel-plate waveguides (GS-DCPPW)—components critical to microwave systems due to their low dispersion properties—are typically computationally complex and extremely time-consuming. To address this limitation, this thesis presents a novel, rapid, and highly practical design methodology based on the Auxiliary Functions of the Generalized Scattering Matrix (AFGSM) for the dimensional synthesis and analysis of these structures. The proposed approach utilizes an equivalent transmission line circuit model rather than conventional, time-consuming full-wave solvers to extract the scattering (S) parameters of the unit cell. By employing the AFGSM method, the passband and stopbands of the structure can be readily identified simply by analyzing the zero-crossings of the auxiliary functions, entirely eliminating the need to solve complex eigenvalue equations. The validity of the algorithm was tested using unit cells optimized for Ku-band and X-band filter applications, with the resulting performances successfully verified against commercial full-wave simulators (CST Microwave Studio and HFSS). Ultimately, the developed method offers a significant speed advantage within the design space—reducing a computational process that would normally take 360 hours down to merely 20 seconds. Furthermore, it demonstrates that it is possible to design highly compact filters with broader stopband suppression capabilities compared to existing alternatives in the literature.